Due to increasing power consumption requirements in mobile phone applications, batteries are used from their nominal voltage value down to a lower value where energy is still stored inside and available for use. For that purpose, regulators and buck converters are used in a wide range of supply voltages. As a result, it is necessary that voltage regulation occur in both large drop-out voltage conditions in which the required voltage is substantially less than the supply voltage and low drop-out conditions in which the required voltage is close to the supply voltage. Step-down direct current to direct current (DC-DC) converters provide good efficiency when used under large drop-out voltage conditions. However, DC-DC converters require a coil to work which increases the resistive path between the battery and the output point to be regulated. As a result, the minimum drop-out voltage between battery voltage and output voltage is quite large. As a consequence, the drop-out voltage between battery voltage and output voltage is limited. In contrast, low drop-out (LDO) regulators have good efficiency with a low drop-out voltage but have poor efficiency with a large drop-out voltage.